Recurrent motion abrading apparatus



Dec. 28, 1954 R. T. osMAN RECURRENT MOTION ABRADING APPARATUS 2 sheets-sheet 1 IN V EN TOR.

Original Filed March 6, 1950 Dec. 28, 1954 R OSMAN 2,697,898

RECURRENT MOTION ABRADING APPARATUS Original Filed March 6, 1950 2 Sheecs-Shee*h 2 United States Patent() I i No. 271,997

Claims. (Cl. 51--170) This invention relates to ebrading apparatus of the oscillating shoe type wherein a at abrasive sheet is caused to execute a recurrent motion and the invention resides more particularly in an improved form of said apparatus in which the abrading shoe is mounted for limited freedom of lateral and longitudinal movement with respect to a frame upon which a driving motor having an output shaft is mounted, a non-rotatable stub shaft being rigidly secured to the frame in spaced parallel relation to the output shaft to provide a mounting for a rotatable driving member surrounding the same, said driving member being connected in driven relation to said output shaft and having an eccentric journal, the latter being connected to and surrounding a journal post secured to the shoe to impart gyrating motion thereto.

This application is a division of my copending application for Oscillating Shoe Abrading Apparatus, Serial No. 147,905, filed March 6, 1950. The invention herein is also related to and in certain aspects constitutesan improvement over the recurrent motion abrader set forth in my Patent 2,441,506, issued May 1l, 1948.

Various forms of apparatus have been proposed and employed in which an oscillating or gyrating abrading shoe has been mounted to be driven by rapidly rotating mechanism that is dependent upon an eccentric member for imparting the oscillating or gyrating movement. In such apparatus a crank shaft having considerable axial extent and carried by bearings both above and below the driven portion thereof is usually employed. The loading of the crank shaft is such as to impose harmful torsional vibration thereon and to impart undesirable rocking couples to the machine as a whole.

It is an object of this invention to provide in a recurrent motion abrading apparatus power translating means for producing gyration of the shoe, which means avoids use of a crank shaft with its inherent torsional weakness.

Another object of this invention is to provide in an apparatus of the class described, a driving means for producing gyration of the shoe which is compact in the vertical direction and in which the vertical spacing of the eccentric members is reduced to a minimum to limit the undesirable rocking couples resulting from such vertical spacing.

Still another object of this invention is to provide in gyrating shoe abrading apparatus a belt driven eccentric actuatorfor the shoe in which bearing means are disposed within the area over which load is applied by belt tension to permit such bearing means to be utilized to full advantage.

This invention is herein set forth and described by reference to the accompanying drawings formingV a part hereof `and in which there is set forth by way of illustration and not of limitation one particular form in which the invention may be embodied.

-In the drawings:

Fig. 1 is a side view in elevation and partly in sectio of an abrading apparatus in which this invention is embodied,

Fig. 2 is a top plan view on a reduced scale of the apparatus shown in Fig. 1,

Fig. 3 is a detail side View in elevation and partly in section of the rubbing shoe, members attached thereto and the actuating eccentric member of the apparatus shown in Fig. l,

- Fig. 4 is a plan view of the apparatus shown in Fig. 3,

Fig. 5 isa rear end view in elevation of the apparatus shown in Figs. 3 and 4.

Fig. 6 is a view in side elevation of the rear portion of the apparatus shown in Figs. 3, 4 and 5,

Fig. 7 is a bottom plan view of the shoe plate of the apparatus shown in Fig. 1, illustrating diagrammatically one form of the movement thereof, and

Fig. 8 is a bottom plan view of the shoe plate of the apparatus shown in Fig. l illustrating diagrammatically another form of the movement thereof.

The form of the apparatus of this invention shown in Fig. l is provided with a frame generally designated 1 on the top of which a motor 2 having a downwardly extending vertical shaft 3 is mounted. Secured to shaft 3 is a Sheave 4 disposed in alignment with and drivingly connected to a sheave 5 by belt 7. Sheave 5 is rotatably mounted beneath frame 1 by means of a bearing 11 carried on stub shaft 12 which is held in place by screw 6.

As will be noted in Figs. l and 4, sheave 5 is divided into upper and lower halves held together by screws 10.

Disposed within the lower half of Sheave 5 is a bearing 13 mounted for rotation on a post 14 which is vsecured in turn to a yieldably mounted shoe driving member 9 by a screw 8. The bearing 13 is disposed eccentrically with respect to the center of bearing 11 so that the post 14 on member 9 is caused to gyrate in a circular path uponI rotation of sheave 5.

As shown in Figs. l and 4, shoe driving member 9 is yieldably attached to a bottom or shoe plate 15 by means of a yieldable rubber mounting 18, held in place by a screw 16 and nut 17 passing through a pedestal 19 secured to plate 15. The mounting 18 is preferably formed with concentric, inner and outer bushings secured to the rubber by vulcanized bonds as shown so as to completely isolate the member 9 from any metallic connection with the shoe 15. ln this way the connection between the eccentric bearing 13 and the shoe 15, at the left hand end of member 9, is rendered yieldable or exible rather than positive.

At its right hand end member 9 is provided with a cup shaped receptacle 21 adapted for the insertion therein of a plug 22 formed of rubber or other resilient or flexible material, said plug being attached to a longitudinally adjustable rod 23. Rod 23 is positioned for slidable movement through upright flanges 24, 25 and 26 of a bracket member 27 which is attached to shoe 15 by rivets 28. A coil spring 29, in compression surrounds rod 23 to bear against collars 30 and 31. Collar 30 is held against motion toward the left with respect to rod 23 by a key as shown, while collar 31 admits rod 23 for free sliding movement therethrough. The plug 22 may be disengaged from contact with the cup shaped right hand end of member 9 and entirely withdrawn therefrom by movement of rod 23 through manipulation of its handle 32 extending therefrom. When rod 23 is pulled back far enough to cause a short transverse pin 33 projecting from rod 23 to be drawn backward through a key way 34, in the flange 26 shown in Fig. 5, the rod 23 may be turned by handle 32 through an arc of 90 degrees to bring the handle 32 into a horizontal plane, whereupon pin 33 is held against the rear surface of flange 26 thus preventing plug 22 from engaging or interfering with member 9.

When the plug 22 is held in engagement with cup 21 a yieldable non-positive connection is established between the right hand end of member 9 and the shoe 15 as well asthe yieldable connection provided at the left hand end of member 9 by the rubber mounting 18. When the plug 9 is withdrawn from the cup 21 a single yieldable connection only is provided between the member 9 and the shoe 15.

As shown in Figs. 1, 3 and 4, there is secured to shoe plate 15, adjacent its forward corners, cylindrical, yieldable rubber mounts 35, the upper ends of which are in turn fastened to frame 1 by screws 38. Because of their composition and cylindrical shape the mounts 35 may be deflected horizontally in any direction, symmetrically, with equal ease. At the same time the mounts 35 act to position the front end of the shoe 15 vertically with respect to the frame 1 and to transmit working thrust from the frame 1 to the shoe 15. Secured to shoe plate 15 adjacent its rear end is a at transverse mounting member 36 of yieldable rubber composition which acts as a vertical positioning and thrust transmitting mountingJ which guides the rear end of the shoe 15 for free displacement lin the longitudinal direction. However, because of the transverse stiffness of member 36 the rear end of the shoe 15 can be displaced but little in the transverse direction. Secured to the top of member 36 is a channel shaped metal member 37, which is secured in turn to the right hand end of frame 1 by screws 39.

When motor 2 is supplied with electric current causing shaft 3 and sheave 4 to rotate, eccentrically disposed bearing 13, driven through belt 7, is caused to move in a circular path thus carrying member 9 around with it in a circular gyrating movement at a point directly concentric with screw 6. Since member 9 is yieldably rather than positively connected to the shoe 15, the motion imparted to the shoe 15 is not of the same configuration and amplitude as that of the eccentric even when plug 22 is in engagement with the cup 21. Under the latter condition the movement imparted to the shoe 15 is such that the same follows a generally elliptical configuration at the end .of the shoe 15 adjacent to the symmetrically deilectible mounts 35, which gyration is of smaller average amplitude than the throw of the eccentric 13.

At the rear or right end of shoe 15 a different action takes place. Because of the specific location of eccentric 13 with reference to the forward and rear ends of shoe plate 15, and because of the resistance to transverse deflection offered by the transverse mount 36, the motion progressively modifies from an elliptical gyration at the front of shoe 15 toward a nearly straight line oscillation as the rear end of the shoe is approached. The general nature of the motion executed by various points in shoe plate 15 under such conditions may be represented by the paths shown in somewhat exaggerated proportions in broken lines in Fig. 7. With this motion, the operator may as previously pointed out, apply pressure to the left end of shoe 15 to cause a rapid cutting action or to the longitudinally moving right end of the shoe 15 to produce a fine finishing action. In either case the yieldable connection between the member 9 and the shoe 15 relieves the bearings of peak stresses and limits the loading which the operator may apply by exerting working pressure, since such yielding action between the member 9 and the shoe 15 will in substantial measure reduce the amplitude of motion of the shoe 15 when overloaded.

The clutch members 21 and 22 are within immediate control of the operator, by manipulation of handle 32, and may be separated or disengaged to provide an even greater degree of transverse yielding in the connection between the eccentric and the shoe 15. With the clutch members disengaged the movement of shoe plate 15 is immediately translated into substantially longitudinal oscillation as illustrated generally in Fig. 8.

To obtain al uniformly fine non-circling abrading action, particularly for a final finishing operation, the operator may thus disengage clutch members 21 and 22 as shown in Fig. 3 and thereby obtain a slower cutting but ner finishing action without any tendency whatever to leave circular-marks in the work.

l claim:

1. In a rubbing machine, a supporting frame, a power driven shaft mounted on said frame, a gyratable rubbing shoe, deflectable mounting means securing said shoe to said frame for lateral and longitudinal movement with respect to said frame, a supporting shaft secured to said frame and extending downwardly therefrom, a mounting bearing carried on and surrounding said shaft, a driving member having an internal downwardly facing socket in which said mounting bearing is seated whereby said driving member is rotatably supported on said shaft, power transmission means connecting the power driven shaft to said driving member, said driving member having an internal upwardly facing eccentric bearing seat, an eccentric bearing mounted in said eccentric bearing seat beneath and eccentrically disposed with respect to the axis of rotation of said mounting bearing, and an upstanding shoe driving post secured to said shoe and receiving thereon said eccentric bearing for causing said shoe to gyrate when said driving member is rotated.

2. in a rubbing apparatus, a frame, a driving motor having an -output shaft mounted toward one end of said frame, a gyratable rubbing shoe, deilectable mounting means securing said shoe to said frame for lateral and longitudinal movement with respect to said frame, a supporting stub shaft secured toward the end of said frame opposite said motor, a mounting bearing secured in rotatable relation on said stub shaft, a driving member having an internal recess for receiving said bearing whereby said driving member is mounted upon said bearing for rotating movement, power transmission means connecting said output shaft to said driving member, said driving member having an internal recess which is eccentric relative to said rst mentioned internal recess and which is immediately adjacent thereto, an eccentric bearing mounted in said eccentric recess and eccentrically disposed with respect to said mounting bearing, and a shoe driving shaft receiving said eccentric bearing and joined to said shoe which is adapted to transmit gyrating movement thereto upon rotation of said driving member.

3. In a rubbing machine, a frame, a driving motor mounted on said frame and having a vertical output shaft extending downwardly through said frame, an output sheave mounted on said output shaft, a gyratable rubbing shoe, deflectable mounting means securing said shoe to said frame for limited lateral and longitudinal movement with respect to said frame, a supporting shaft secured to said frame and extending downwardly relatively thereto, a driving member comprising a pulley having a bearing mounted therein which is received on said supporting shaft to connect said driving member therewith for rotation relative thereto, a transmission belt drivingly connecting said output sheave and said pulley,

said driving member also having a second bearing therein which is eccentric to said supporting shaft, and an upwardly extending shoe driving post secured `to said shoe and receiving thereon said second bearing to form an eccentric driving connection between said shoe and said driving member for causing said shoe to gyrate upon rotation of said motor output shaft.

4. In a rubbing machine having a supporting frame, an oscillatable rubbing shoe, liexible means connecting said shoe to said frame for oscillating movement in a fixed plane, a power driven shaft mounted in said frame, a depending support shaft mounted on said frame in offset relation to the power driven shaft, an upstanding post on said rubbing shoe having its axis offset relative to the axis of said support shaft, a drive member rotatably supported on said depending shaft and connected to said upstanding post, said drive member comprising upper and lower portions secured in face-to-face relation, a shaft receiving recess in said upper portion and a post receiving recess in said lower portion, said shaft and post receiving recesses being in offset relation and each terminating in an internal bearing receiving recess, bearings in said internal recesses which are mounted on said shaft and said post, respectively, and a driving connection between said power driven shaft and said drive member.

5. In a rubbing machine having a supporting frame, a rubbing shoe, flexible means connecting said shoe to said frame for oscillating movement relative thereto, a power driven shaft mounted on said frame, a depending support shaft mounted on said frame in offset relation to the power driven shaft, an upstanding post on said rubbing shoe having its axis offset relative to said support shaft, a drive member rotatably connected to said depending shaft and said upstanding post, said drive member comprising upper and lower portions, a shaft receiving recess extending into said upper portion and a References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,103,444 Bauch Dec. 28, 1937 2,270,309 Kehle Jan. 20, 1942 2,284,671 Meinzer June 2, 1942 2,367,668 Champayne Jan. 23, 1945 2,441,506 Osman May' 11, 1948 2,517,548 Dobson Aug. 8, 1950 2,565,658 Hilger Aug. 28, 1951 2,614,369 Robins Oct. 21, 1952 

